Fire extinguisher



April 10, 1951 T. A. HENSHAW 2,548,157

FIRE EXTINGUISHER Filed Jan. 2L 1948 J n I I (L /O z E I J 5772 Patented Apr. 10, 1951 ATENT OFFICE .rIaE nx'rmonrsnca Thomas A. Henshaw, Elland, England, assignor to Nu-Swiit, Limited, London, England Application January 21, 1948, Serial No. 3,5'70 In Great Britain January 18, 1947 Section 1, Public Law 690, August 8, 1946 Patent expires January 18, 1967 The invention relates to fire extinguishers of the type in which discharge of liquid from a container is effected by the release into the container of a charge of gas under pressure.

As hitherto constructed, fire extinguishers of the type referred to have usually comprised a container for liquid, and a removable head permitting access to the containerforfilling and inspection purposes and for the introduction to the container of a cartridge or container'for a compressed gas charge, such cartridge or'container having a sealing disc adapted to be ruptured by a piercing member carried by, and operable from the exterior of, the head.

The present invention has for its object to provide an improved and simplified fire extinguisher of the type referred to which will possess many advantages over the known constructions.

A fire extinguisher according to the invention is characterised mainly by'the fact LthatLtheusual closing head. for the liquid container is dispensed with, and in that a cartridge carrying'thegas charge or a container or holder for the cartridge,

instead of being located within the liquid container and operated by a'piercer operable from the exterior of a closing head,.forms itself a readily detachable closure for an orifice in the liquid container and being so proportioned as. to completely fit the orifice which is of .suflicient Size to allow rapid filling and easy inspection, and whilst maintaining or constituting an effective seal for such container during operation of the extinguisher, is capable of sufiicient axial movement under manually-applied pressure as to enable a sealing .disc carried by its lower end to be pierced by a stationary piercing member located within the container.

The accompanying drawing shows, in sectional elevation, a constructional embodimentof the invention.

Referring to the drawing a liquid container at of appropriate capacity has in its upper end an opening a of sufiicient diameter to admit of the insertion of a cartridge containing a charge of compressed gas suiiicient to effect, on release, expulsion of the liquid in the container through a dip tube and a suitable discharge nozzle, the latter being preferably carried by a flexible hose or connection not only for convenience in operating the container but for a further reason which will be mentionedshortly. As the dip tube and discharge nozzle are or may be of ordinary and well-known construction, it has not been deemed necessary, for the understanding of the invention, to show them.

9 Claims. (Cl. 169-331 The actual gas cartridge or container b is housed in a two-part holder 0, c, the upper part c which, when the gas container b is in position, is exposedito the exterior of the-extinguisher, be-. ing rotatable with respect to the other or lower part c, and the two parts being held in associated or assembled relation by means of a shear pin (1 of known or limited strength. The top half 0 could be screwed to the lower half 0 if preferred, and it may be made of transparent material.

The gas charge container b is provided with a neck or reduced diameter portion 12 which is threaded externally and adapted to be screwed into. an internally-threaded opening 0 in the bottom of the lower part c of the holder. A plug e, screwed into-the neck I) of the gas container, has an axial passage e .thelower end of which is provided with a sealing disc 1 and, between the lower extremity of the gas container neck b. and a shoulder c on thelower-part c of the holder on which it rests, there is secured a thin metal diaphragm g. This diaphragm not only constitutes an additional seal for the gas but also acts to indicate any leakage-of gas there maybe around the closing plug, any such leakage causing an outward bulging orit may be bursting of the diaphragm. I

A supporting member h, screwed into the opening a in the liquid container, has a cupped upper surface h to receive the lower part c of the gas charge holder, and in the bottom of this cupped portion h there is provided a central opening b in'which a cylindrical portion or neck c at the bottom of the lower part of the holder ca slide. A bridge member 2', detachably secured to the underside of the supporting member by screws z", carries an axially-disposed, upwardly-mm looting pierce a and forms a platform to support the lower end of a coiled spring is confined between the platform z' and the shoulder 1' in the neck portion of the lower part c of the-gas charge holder, said spring is functioning to hold .thesealing disc anddiaphragm g of the gas charge holder'- awayyfrom the piercer 5i but permitting the said holder to slide inwardly, against externally-applied pressure, to cause the diaphragm and the sealing disc to be punctured and the gas charge to be released.

The lower extremity of the neck portion c of the lower part c' of thegas'charge holder is provided with radially-extending lugs c 05, adapted to engagewith vertically extending bayonet slots 11!. in the'holder in such manner as to permit of the r dy nt uct o of the gas ar e h ld but to resist removal of said holder when the gas charge has been released, and the interior of the extinguisher is under pressure. The spring is also assists to expel the gas charge holder when its lugs have been disengaged from the bayonet slots.

In order to prevent accidental pressing inwardly of the gas charge holder 0, c, a safety pin n extending through an opening in the container body into a recess or opening in the holder is connected to the discharge nozzle of the extinguisher, so that as the nozzle, which is normally held detachably in position against the outer surface of the extinguisher, is removed prior to operation of the extinguisher the safety pin n is withdrawn and the gas charge holder freed for inward movement.

Between the lower part c of the gas charge holder and the opening in the supporting member h in which it fits, there is provided an inverted U washer p of suitable shape and material which, when the extinguisher is not in use, provides a sufiicient vent to permit of building up of undesired pressure within the extinguisher but which, when the gas charge is released, functions to provide a seal against escape of pressure between the charge holder and the supporting member.

A suitable space 1' is provided between the actual gas cartridge and the upper part c of the charge holder, so as to afford in ulation against the low temperature set up when the gas is released suddenly.

Should any attempt be made to remove the gas charge holder when the gas charge has been released, and pressure exists in the container, the upper part c of the holder will rotate and shear the holding pin d, leaving the cartridge and the lower part of the holder in position and preventing escape of pressure.

The thread by which the gas cartridge 1) is secured in the lower part c of the holder is provided with longitudinal slots to allow a gradual escape of pressure should the cartridge be removed whilst any pressure exists in the extinguisher.

Among the advantages presented by the improved extinguisher are that visual indication is always had that a charge is in position, thus avoiding the possibility present in the old constructions of refilling the outer container with liquid and replacing the closing head without inserting a gas charge; the gas charge can be quickly removed and replaced; the gas charge can be easily inspected and renewed if faulty; the diaphragm between the gas cartridge and the shoulder of the holder on which it rests seals the cartridge against possible corrosion from the liquid in the extinguisher and adequate provision is made against accidental release of the gas charge and against injury through opening up of the extinguisher when under pressure.

I claim:

1. A fire extinguisher, comprising in combination, a container for the fire extinguishing liquid; an opening in the upper part of the container; a supporting member secured in said opening; a central opening provided in said supporting member; a gas cartridge holder, the said cartridge holder being made in two halves, one rotatable in relation to the other; a shear pin normally connecting said two halves and holding them against relative rotation; a depending neck provided on said cartridge holder and adapted to slide in thej central opening of the supporting member; a piercer fixedly mounted on said supporting member so as to be disposed in said central opening and opposite the inner end of said neck of the cartridge holder; a gas cartridge carried Within said holder and having a protruding portion extending into said open neck; an outlet Channel p o ded on said gas cartridge in said protruding portion; a sealing disc provided across said outlet channel; and resilient means for urging said cartridge holder outwardly so as to normally hold said sealing disc clear of said piercer.

2. A fire extinguisher, comprising in combination, a container for the fire extinguishing liquid; an opening in the upper part Of the container; a supporting member secured in said opening; a central opening provided in said supporting member; a gas cartridge holder, the said cartridge holder being made in two halves, one rotatable in relation to the other; a shear pin normally connecting said two halves and holding them against relative rotation; a depending neck provided on said cartridge holder and adapted to slide in the central opening of the supporting member; a bridge piece carried by the supporting member across said central opening of the same; a piercer fixedly mounted on said bridge piece so as to be disposed in said central opening and opposite the inner end of said neck of the cartridge holder; a gas cartridge carried within said holder and having a protruding portion extending into said open neck; an outlet channel provided on said gas cartridge in said protruding portion; a sealing disc provided across said outlet channel; and resilient means for urging said cartridge holder outwardly so as to normally hold said sealing disc clear of said piercer.

3. A fire extinguisher, comprising in combination, a container for the fire extinguishing liquid; an opening in the upper part of the container; a supporting member secured in said opening; a central opening provided in said supporting member; a gas cartridge holder, the said cartridge holder beingv made in two halves, one rotatable in relation to the other; a shear pin normally connecting said two halves and holding them against relative rotation; a depending neck provided on said cartridge holder and adapted to slide in the central opening of the supporting member; a bridge piece carried by the supporting member across said central opening of the same; a piercer fixedly mounted on said bridge piece so as to be disposed in said central opening and opposite the inner end of said neck of the cartridge holder; a gas cartridge carried within said holder and having a protruding portion extending into said open neck; an outlet channel provided on said gas'cartridge in said protruding portion; a sealing disc provided across said outlet channel; and a coil spring resting on said bridge piece with one of its ends and acting with the other end on the inner end of said neck of said cartridge holder and urging said cartridge holder outwardly so as to normally hold said sealing disc clear of said piercer.

4. A fire extinguisher, comprising in combination, a container for the fire extinguishing liquid; an opening in the upper part of the container; a supporting member secured in said opening; a central opening provided in said supporting member; a gas cartridge holder, the said cartridge holder being made in two halves, one rctatable in relation to the other; a shear pin normally connecting said two halves and holding them against relative rotation; a depending neck provided on said cartridge holder and adapted to slide in the central openingof the supporting member; a piercer fixedly mounted onsaid supporting member .so. as to be disposed in said central opening and opposite the inner end of said neck of the cartridge holder; a gas cartridge carried withinsaid holder andhaving a protruding portion extending into said open neck; an (outlet channel provided on said gas cartridge in said protruding portion; a sealing disc provided across said outlet channel and within the same; a shoulder provided within said depending neck of said cartridge holder; a diaphragm nipped between said shoulder and the inner end of said protrud ing portion of said gas cartridge; and resilient means for urging said cartridge holder outward- 1y so as to normally hold said sealing disc clear of said piercer.

5. A fire extinguisher, comprising in combination, a container for the fire extinguishing liquid; an opening in the upper part of the container; a supporting member secured in said opening; a central opening provided in said supporting member; a gas cartridge holder, the said cartridge holder being made in two halves, one rotatable in relation to the other; a shear pin normally connecting said two halves and holding them against relative rotation; a depending neck provided on said cartridge holder and adapted to slide in the central opening of the supporting member; a piercer fixedly mounted on said supporting member so as to be disposed in said central opening and opposite the inner end of said neck of the cartridge holder; a gas cartridge carried within said holder and having a protruding portion extending into said open neck; an outlet channel provided on said gas cartridge in said protruding portion; a sealing disc provided across said outlet channel; resilient means for urging said cartridge holder outwardly so as to normally hold said sealing disc clear of said piercer; radial lugs provided on said depending neck of the cartridge holder; and bayonet slots provided in the peripheral wall of said central opening of the supporting member for cooperating with said lugs for the purpose of enabling the holder to be readily detached from and inserted into the supporting member when the interior of the liquid container is not under pressure, and of preventing removal of the holder when the interior of the container is under pressure.

,6. A fire extinguisher constructed in accord ance with claim 1 wherein said supporting member encloses said gas cartridge and wherein said gas cartridge is spaced with its upper end from the interior surface of the upper end of said supporting member.

7. A fire extinguisher, comprising in combination, a container for the fire extinguishing liquid; an opening in the upper part of the container; a supporting member secured in said opening; a central opening provided in said supporting member; a gas cartridge holder, the said cartridge holder being made in two halves, one rotatable in relation to the other; a shear pin normally connecting said .two halves and holding them against relative rotation; a depending neck pro vided on said cartridge holder and adapted to slide in the central opening of the supporting member; a bridge piece carried by the supporting member across said central opening of the same; a piercer fixedly mounted on said bridge piece so as to be disposed in said central opening and opposite the inner neck of the cartridge holder; a gas cartridge carried within said holder and having a protruding portion extending into said open neck; an outlet channel provided on said gas cartridge in said protruding portion; a sealing disc provided across said outlet channel; a shoulder provided within said depending neck of said cartridge holder; a diaphragm nipped between said shoulder and the inner end of said protruding portion of said gas cartridge; and resilient means for urging said cartridge holder outwardly so as to normally hold said sealing disc clear of said piercer.

"8. A fire-extinguisher, comprising in combination, a container for the fire extinguishing liquid; an opening in the upper part or" the container; a supporting member secured in said opening; a

central opening provided in said supporting member; a gas cartridge holder, the said cartridge holder being made in two halves, one rolatable in relation to the other; a shear pin normally connecting said two halves and holding them against relative rotation; 2. depending neckprovided on said cartridge holder and adapted to slide in the central opening of the supporting member; a bridge piece carried by the supporting member across said central opening of the same; a piercer fixedly mounted on said bridge piece so as to be disposed in said central opening and opposite the inner neck of the cartridge holder; a gas cartridge carried within said holder and having a protruding portion extending into said open neck; an outlet channel provided on said gas cartridge in said protruding portion; a sealing disc provided across said outlet channel; a shoulder provided within said depending neck of said cartridge holder; a diaphragm nipped between said shoulder and the inner end of said protruding portion of said gas cartridge; and a coil spring res.ing on said bridge piece with one of its ends and acting with the other end on the inner end of said neck of said cartridge holder and urging said cartridge holder outwardly so as to normally hold said sealing disc clear of said piercer.

9. A fire extinguisher, comprising in combination, a container for the fire extinguishing liquid; an opening in the upper part of the container; a supporting member secured in said opening; a central opening provided in said supporting member; a gas cartridge holder, the said cartridge holder being made in two halves, one rotatable in relation to the other; a shear pin normally conmeeting said two halves and holding them against relative rotation; a depending neck provided on said cartrid e holder and adapted to slide in the central opening of the sup-porting member; a bridge piece carried by the supporting member across said central opening of the same; a piercerv fixedly mounted on said bridge piece so as to be disposed in said central opening and opposite the inner neck of the cartridge holder; a gas cartridge within said holder and having a protruding portion extending into said open neck; an outlet channel provided on said gas cartridge in said protruding porlion; a sealing disc provided across said outlet channel; a shoulder provided within said depending neck of said cartridge holder; a diaphragm nipped between said shoulder member When the interior of the liquid container 5 is not under pressure, and of preventing removal of the holder when the interior of the container is under pressure.

THOMAS A. HENSHAW.

REFERENCES CITED The following references are of record in the file of this patent:

Number Number 8 UNITED STATES PATENTS Name Date Norgren May 14, 1935 FOREIGN PATENTS Country Date Great Britain Feb) 15, 1916 

